Lens grinding and polishing machine.



No. 886,212. PATENIED APR.28 ,-1908.

I W. F. HOFFMAN. I I LENS GRINDING AND POLISHING MACHINE.

APPLICATION FILED SEPT. 12, 1906.

2 SHEETSS1IBET 1.

WWW 1 3% No. 886,212. PATENTED APR. 28, 1908.

w. F. HOFFMAN.

LENS GRINDING AND POLISHING MACHINE.

APPLICATION FILED SEPT. 12, 1906.

2 SHEETS-SHEET 2.

3 mun for ifllz'iz/m man Witnesses Jj JwfiW 3% @(ZMM W W invention; it" being, however, understood UNITED LENS GRINDING AND POLISHING MACHINE.

Specification of- Letters Patent.

Patented Apri1 28,'1908.

Application filed September 12, 1906. Serial No. 334,332.

To all whom it may concern:

Be'it known that I, WALTER F. HOFFMAN,

. a citizen of the United States, residing at Minneap'olis, in the countyof Hennepin and State of Minnesota, have invented new and useful lmprovements in Lens Grinding and Polishing Machines, of which the following is a specification.

This invention relates to machines for grinding and polishing optical lenses, such as toric, spherical, bifocal, trifoc'al and cylindrical lenses; and it has for its object to provide an organized machine, of simple and inexpensive construction, whereby a considerable number of lenses may be simultaneously ground or polished in any desired mannor with convex or concave surfaces, and with focuses of any desired and predetermined radius.

A further object of the invention is to provide asimple and efficient machine whereby multifocal, such as bifocal or trifocal lenses, may be ground and polished in such a mannerthat the weaker and the stronger curves shall blend into one another in imperceptible lines and curves, making these curves with a true optical center, and without the objectionable prismatic cfie'ct common to such lenses, said lines and curves being practically invisible.

. A further object of the invention is to provide simple and improved means for automatically supplying the needed abrading material to the grinding and polishing sur-' faces, thereb saving the work of an attendant and ena ling a number of the machines to be operated with the services of but one attendant.

Further objects of the invention are to simplify and lmprove the construction and operation of this class of machines.

With these and other ends in view which will readily appear as the nature of the invention is better understood, the same cons'ists in the improved construction, arrange- .ment and combination of parts which will be hereinafter fully described, and particularly pointed out in the'cla'imsn In the accompanying drawings has'been illustrated' a simple and preferred form of the that no limitation is necessarily made to the recise structural details therein exhibited,

ut that changes, alterations and modifications within the scope of the invention may be resorted to, when desired.

In the drawings: Figure 1- is a front elevation of a lens grinding and polishing machine embodying the principles of the invention. Fig. 2 is a vertical longitudinal sectional view of thesame. Fig. 3 is a plan sTArns rignnr orriou.

view showing'a form of grinding wheel hav ing various curves. Fig. 4 is a face view of one of the horizontal rotary disks used in connection with the invention, showing several lenses in position forbifocal grinding by a wheel of the character shown in Fig. 3.

Fig. 5 is'a perspective detail view of one of the reciprocatory disks or holders for grind ing toric or cylindrical lenses.

- Corresponding parts in the several figures are denoted by like characters of reference. I The improved machine, in the simple and preferred form shown in the drawings, includes a table or bed-plate, 1, having depending brackets, 2, 2, that constitute bearings for a shaft, 3, which is longitudinally slidable in said bearings. The table or bedplate is also providedwith bearings, 4, upon its upper side for a driven shaft, 5, having pulleys, as 6, whereby it may be driven at the requisite speed from any convenient source of power. p

The shaft 3 has a gear-wheel, 7, meshing with a pinion, 8, upon the driven shaft 5,

from which the said shaft 3 is thus driven at reduced speed; the pinion 8 being of sufiicient length to permit the shaft 3 to recipt y rocate longitudinally, as will be presen shown, without danger of becoming disengaged from, or out of mesh with the spurwheel 7.

Secured upon the shaft 3, in an inclined position, is a cam-wheel or disk, 9, the periphery of which engages between a-' air of lugs, 10, 10, upon the under side of t e bed plate, thus serving, when the shaft 3,is rotated, to impart to said shaft a longitudinal reciprocatory movement, the extent of said movement or 'throw being governedby the inclination of the disk or cam wheel.

v .The shaft 3 carries near its front end black-- ets,11', having bifurcated arms, as 12, rov'ided with terminal e es, 13-, whereby t ey are hingedly mounte upon the shaft; the

lattenbeing provided with annular flanges-or.

collars, 14, whereby longitudinal displacement of the brackets is prevented. The

"main shaft 5. The shafts 23 are brackets are provided with hooks, 15, adaptedto be connected with springs, 16, depending from the bedlate, for the purpose of retaming the brac ets resiliently in a raised position, as will be presently more fully described. r

The driven shaft 5 projects at the front end of the frame of the machine, and u on the projecting front end there is detacha bly mounted a wheel, 17, which may be used either as a grindin and polishin wheel, or for the purpose ofho ding lenses that are to be ground and olished, according to the character of the lenses that are to be manufactured. The Washer, 18, is inter osed between the wheel 17 and the front en of the frame,- in order to eflect a reduction of friction; and

the wheel, which is held in osition upon the shaft by a nut, 19, threaded upon the latter, is held against rotation by a key or spline, 20.

The bed plate or frame of the machine is provided with a plurality of radially extend.- mg arms, 21, havin boxes or bearings, 22, in which are journale shafts, 23, which are disposed radially with relation to the driven rovided near their outer extremities with pu eys, 24, connected by means of belts or hands, 25,

3' .with pulleys, 26,- upon the shaft 5, from which motion will in this manner be transmitted to the shafts 23; the driving belts or bands 25 areguided over guide pulleys, 27, journaled in brackets, 28, upon the rear sides of the arms 21. It will be understood, that" within the scope of the invention any well known mechanical means other than that which has been described and illustrated,

may be employed for the urpose of transmitting motion from the sha t 5 to the shafts23.

Upon the inner ends of the shafts 23 there are mounted disks, 29,- which will serve as lens holders or forgrinding or olishing purposes,.according to the kind of enses that are to be manufactured, The disks 29 are prefs, and they are turned, planed, or otherwise ormed with curved or concave faces of any desired predetermined radius. The disks' 29 have been shown provided with sockets, 30, adapted for engagement with the non-circular inner extremities. of the shafts 23, upon which the said disks.

\ may thus be convenientl mounted in such a manner as to be readil stitution, when desire of other of a different etached for the subshape, or having faces of a different curvature.

- The brackets 11 socketed attheir outer extremities, as will be seen at 31, for "the recelpition of shanks, 32, formed upon disks, 33 w ch are thereby mounted detachably upon the saidbrackets; said disks beingutili'zed, like the disks 29, for i P to e operated. upon. Ihese disks, which 'matically, the erned by prope connection with t ding or llshmg -ses or forthe purgb siia of oldi lenses.

are preferably of s uare contour, as will be best seen in Fig. 5 o the drawings, have concave faces which are turned, planed or otherwise formed with reference to grinding toric or cylindrical lenses.

' The wheel 17 may be provided with a curved face of any desired radius, as will be seen at 34 in Fi 2; or the face of said wheel may be forms witha plurality of curves, 35, 36, 37, as seen in Fig.3; the latter bein the construction employed when multifoca lenses are to be concavely ground or polished. In like manner the faces of the disks 29 may be formed with a plurality of curvatures, for the purpose of grinding -orpolishing convex multifocal lenses.

The frame of the machine carries a suitably supported receptacle or hopper, 38, constituting a container for the abrading material used for inding or polishing purposes, and equipped with a gate, 39, carried by a pivoted stem, 40, which is actuated by a spring, 41, whereby the gate is held, normally, in a closed position. The stem 40 isprovided with a radial arm, 42, lying in the path of a lug, 43, upon one of the shafts 23, the rotation of which will thus serve intermitto open the gate 39 for the escape of a te'ntll-y sma quantit of abrading material to the face of the w eel 17 which rotates beneath the hop er orreceptacle' By this simple device t e abrading'. material is fed autouantity being readily govi'ly regulating the size of the escape opening. .The services of an attendant to supply the abrading material will thus beidispensed with, and this part of the work with absolute regularity tion will be readily understood by those skilled in the art to which it appertains. erably of circular contour, as will bebest seenin Fig. 4 of'the draw Thewheel 17 as well as the disks '29and 33, are used interchangeably for and. olishing purposes, and for the purpose of holding and supporting the glasses} or .crys- V tals that are to be operated upon; the same "being cemented in the usual manner upon the faces of the wheel or the disks, .as the .case may he.

ished, the crystals will be supported upon the when convex surfaces are to be .ground ,and polished, the crystals will be It will beunderstood, that when concave surfaces are to be 'ground and polcemented-upon the face of the wheel 17;" the faces of the disksas well as the .wheel being i formed with regular predetermined curves.

ofany desired shape.- .As will be seen in 4, the disks are preferablymade of a calgacityto hold a plurality of lenses, or crysta which have beenindicated by 44 in saidfigure. The disks 29 are messed radially against the face of the whee 17 by the tenis sion of the driving bands or belts 25, or, if preferred, by suitable independent means provided for the purpose; and, being rotated against the face of the wheel, and the faces of the wheel and the disks having been properly constructed, multifocal lenses will thus be formed in which the various curves will be imperceptibly blended, and. the prismatic efiects, usually resent in this class of lenses, avoided. It wil also be seen, that by this machine, a large number of crystals may be simultaneously ground or polished, thus greatly reducing the expense of manufacture, while the quality of the product is in nowise impaired, but, on the contrary, vastly improved, es ecially as regards the qualityof the multi ocal lenses. Another important advantage of this invention is that by this improved machine a large number of lenses of different kinds, and with different curvatures, may be simultaneouslyprepared, thus largely reducing the ex ense ofmanufacture.

Having thus descri ed my invention, -I claim and desire to secure by Letters Patent of the United States 1. In a machine of the class described, a vertically disposed wheel supported for rotation, disk-carrying shafts supported for rotation radially to the wheel, a receptacle or hopper supported to dischar e its contents in the direction of the face of -t e wheel, a gate for said hopper having a sprin actuated stem where y said gate is held normally closed, an arm extending radiall fromthe gate stem, and a lug upon one o' the radial shafts for intermittent engagement with said arm.

2. In a machine of the class described, a

vertically disposed grinding and polishing wheel supported for rotation, a bracketsupported for reciprocation ina plane parallelv to the axis of the wheel, a disk carried by the bracket, and means for forcin .the latterjresiliently in the direction of t e face of the wheel. 1

3. In a machine of the class described, a

driven main shaft, a counter-shaft slidably resiliently in the direction of the face of the wheel.

- for forcing the disk in the direction of the'face 4. In a machine of the class described, a grinding and polishing wheel supported for rotation, a bracket su ported for reciprocation, a disk carried by are bracket, and means of the wheel.

5. In a machine ofthe class described, a grinding and polishing wheel supported for rotation, a bracket supported for reciprocation in a lane paralle to the axis of the wheel, a disk carried by the bracket, and means for forcing the disk in the direction of the face of the wheel.

6. In a machine of the class described, a main shaft, a wheel sup orted upon the main shaft, a counter shaft s idably and revolubly sup orted, means for rotating the counter. sha t, means for reciprocating the counter sliaft when it is rotated, and a disk carrying bracket mounted upon the counter shaft.

7. In a machine of the class described, a main shaft, a wheel sup orted upon the main shaft, a counter shaft s idably and revolubly sup orted, means for rotating the counter sha t, means for reciprocating the counter shaft when .it is rotated, a disk carrying bracket mounted upon the counter shaft, and means for forcin the disk carrying bracket in-the direction 0 the face of the wheel.

, 8. In a machine'of the class described, a driven main shaft, a wheel supported upon the main shaft, a counter shaft slidably and revolubly supported, said counter shaft receiving rotary motion from the main shaft, means for reciprocating the counter shaft when it is rotated, and a disk carrying bracket mounted upon the counter shaft.

9. In a inachine of the class described, a grinding and polishing wheel supported for rotation, a bracket su orted for reciprocation, and a disk" carrierFBy the bracket.

10. In a machine of the class described, a wheel supported for rotation, a disk carr ing shaft supported for rotation, a receptac e or hop er supported to discharge its contents in tiie directionof the face of the wheel, a gate for the hopper, and means carried by the shaft for intermittently opening thegate.

11. In a machine of theclass described, a table orbottom plate, a driven or main shaft journaled on the table or bottom plate, a

-and means for forcing the disk carrying bracket in the direction of the face of the -wheel.

In testimony whereof, I-[afiix my signature in presence of two witnesses.

WALTER F. HOFFMAN. Witnesses:

JOHN DWA'N, HATTIE E. SWAILES.

lugs upon the upon the main shaft, a disk ca 

